feat(adapters): external adapter plugin system with dynamic UI parser

- Plugin loader: install/reload/remove/reinstall external adapters
  from npm packages or local directories
- Plugin store persisted at ~/.paperclip/adapter-plugins.json
- Self-healing UI parser resolution with version caching
- UI: Adapter Manager page, dynamic loader, display registry
  with humanized names for unknown adapter types
- Dev watch: exclude adapter-plugins dir from tsx watcher
  to prevent mid-request server restarts during reinstall
- All consumer fallbacks use getAdapterLabel() for consistent display
- AdapterTypeDropdown uses controlled open state for proper close behavior
- Remove hermes-local from built-in UI (externalized to plugin)
- Add docs for external adapters and UI parser contract

server/src/app.ts

@@ -29,6 +29,7 @@ import { llmRoutes } from "./routes/llms.js";
 import { assetRoutes } from "./routes/assets.js";
 import { accessRoutes } from "./routes/access.js";
 import { pluginRoutes } from "./routes/plugins.js";
+import { adapterRoutes } from "./routes/adapters.js";
 import { pluginUiStaticRoutes } from "./routes/plugin-ui-static.js";
 import { applyUiBranding } from "./ui-branding.js";
 import { logger } from "./middleware/logger.js";
@@ -226,6 +227,7 @@ export async function createApp(
       { workerManager },
     ),
   );
+  api.use(adapterRoutes());
   api.use(
     accessRoutes(db, {
       deploymentMode: opts.deploymentMode,